Man pollutes his environment in various ways. For example, some

Man pollutes his environment in various ways. For example, some people dirty the air wiih gases and smoke. The machines and motor vehicles they operate fill the air with 1______ noise. 2______ people poison the water with chemicals and other 3______. Still others damage the soil with too many 4______.5______,people ruin natural beauty by 6______ rubbish on the land and in the water. Today, millions of people have become alarmed by the dangers of 7______, and large numbers of people are trying to reduce it.
But it is not easy to reduce pollution 8 much of it is caused by things that 9______ people. For example, exhaust from automobiles causes a large percentage of all air pollution, but the automobiles provide 10______ for millions of people. 11______ discharge much of the materials that 12______ air and water, but factories 13______ jobs for people. Too much chemical fertilizer can 14______ soil, but fertilizers are important 15______ to the growth of crops.
However, people have already found several ways in which pollution can be gradually 16______. Scientists and engineers have found some ways to 17______ the amount of pollution that 18______ things as automobiles and factories cause. Governments can pass laws that 19______ businesses and individuals to stop or reduce certain polluting 20______.
17
A、lessen
B、dismount
C、make
D、pay
【正确答案】：A
【题目解析】：根据题意，科学家和工程师已经找到一些方法来减少污染量，lessen减少最符合题意。dismount下马，下车。答案为A。